无法定义运算符

Question

我有以下简单类型:

module Structures
    type Point2D<'T> (x : 'T, y : 'T) =
        member this.X = x
        member this.Y = y
        member this.IsEqualTo (p : Point2D<'T>) =
            (this.X = p.X) && (this.Y = p.Y)

但Visual Studio(2012试用版)在名称"IsEqualTo"下放置一条红色波浪线,在"this.X"下放置一条蓝色波浪线.

红色波浪线的错误消息如下:

通用成员IsEqualTo已在此程序点之前的非均匀实例化中使用.考虑重新排序成员,以便首先发生此成员.或者,明确指定成员的完整类型,包括参数类型,返回类型和任何其他通用参数和约束.

蓝线的消息是:

类型参数缺少约束'when'T:equality'

我已经尝试在所有其他成员之前放置"IsEqualTo",但错误仍然存​​在.

我猜这个错误与=登录this.X = p.X工作在泛型类型上的事实有关,'T但我似乎无法纠正它.

预先感谢您的帮助.

Answer 1

type Point2D<'T when 'T : equality> (x : 'T, y : 'T) =
    member this.X = x
    member this.Y = y
    member this.IsEqualTo (p : Point2D<'T>) =
        (this.X = p.X) && (this.Y = p.Y)